Construction technology often employs unitized curtainwall units that are anchored to the building structure. A curtainwall system is a lightweight exterior cladding that is connected to the building structure, usually from floor to floor. It can provide a variety of exterior appearances. Curtainwalls are designed to accommodate structural deflections, control wind-driven rain and air leakage, minimize the effects of solar radiation, and provide for low maintenance long term performance.
The curtainwall is an external, lightweight, generally non-loadbearing wall that is hung from a frame rather than built up from the ground. The framework it shields, and to which the curtainwall is connected, usually is made of concrete or steel. Curtainwalls may be used with any suitable structure but are typically used in high-rise buildings. Typically light, the use of curtainwalls reduces the forces on the foundations, making the building lighter. Curtainwalls may be a form of prefabricated construction, and can be installed with relative ease, even at significant heights above the ground.
Curtainwalls may be produced in a fully ready-to-install form, in which case they may be installed as discrete building units (curtainwall units). The ready-to-install form is referred to as a unitized system. The unitized system is costly to ship due to its large size and heavy weight. Furthermore, typically only a limited number of units can be packed into each shipping container. To minimize the problems associated with shipping, unitized systems may be manufactured to a point less than complete at a manufacturer's location and then shipped to an assembly facility where they are completed. The assembly facility may be located generally proximate to the installation site. Any component parts are wet sealed to form a unit at the assembly facility. Wet sealing typically comprises laying the unit flat, sealing, clamping, and maintaining the unit in position for first and second cure times. The first cure time is generally approximately one hour during which no movement of the unit is permitted. Because the units are laid flat during wet sealing and cannot be moved at all during at least the first cure time, the assembly facility typically must have relatively large square footage. Further, because the assembly facility is generally located proximate the installation site, the labor hired for the facility is typically new for each building. This can lead to concerns regarding quality assurance and quality control (QA/QC).
Another type of curtainwall system is a stick system. In a stick system, each component part of a curtainwall is shipped to the installation site and the curtainwall is built up at the installation site. Thus, a stick system is labor intensive at the installation site. The construction site also presents a more challenging environment for QA/QC including but, not limited to, application of wet sealants at the construction site.
It would be desirable to provide a system that allows for partial assembly of components, including application of wet sealant, at a low cost facility with high quality control standards and then final assembly of the complete curtainwall unit at a small facility close to the construction site or at a dedicated area of the construction site itself, in either case without the need for application of wet sealant. In addition to better quality control, this would allow for higher through put and minimal space needs at the final assembly location.